This invention relates generally to the field of electronic film processing and more particularly to an improved system and method for digital film development using visible light.
Images are used to communicate information and ideas. Images, including print pictures, film negatives, documents and the like, are often digitized to produce a digital image that can then be instantly communicated, viewed, enhanced, modified, printed or stored. The flexibility of digital images, as well as the ability to instantly communicate digital images, has led to a rising demand for improved systems and methods for film processing and the digitization of film based images into digital images. Film based images are traditionally digitized by electronically scanning a film negative or film positive that has been conventionally developed using a wet chemical developing process, as generally described below.
Undeveloped film generally includes a clear base and one or more emulsion layers containing a dye coupler and a photosensitive material, such as silver halide, that is sensitive to electromagnetic radiation, i.e., light. In color films, independent emulsion layers are sensitized to different bands, or colors, of light. In general, one or more emulsion layers are sensitized to light associated with the colors of red, green and blue. When a picture is taken, the photosensitive material is exposed to light from a scene and undergoes a chemical change. The greater the intensity of light interacting with the photosensitive material, the greater the chemical change in the photosensitive material. The photographic film can then be chemically processed to produce a fixed image of the scene based on this chemical change.
In a traditional wet chemical developing process, the film is immersed and agitated in a series of tanks containing different processing solutions. The first tank typically contains a developing solution. The developing solution chemically reacts with the exposed silver halide to produce elemental silver grains in each emulsion layer of the film. The metallic silver forms a silver image within each emulsion layer of the film. The by-product of the chemical reaction combines with the dye coupler in each emulsion layer to create a dye cloud. The color of the dye cloud is complementary to the band of light the emulsion layer has been sensitized to. For example, the red sensitized layer typically produces a cyan dye image, the green sensitized layer a magenta dye image, and the blue sensitized layer a yellow dye image. The density of the silver image and the corresponding dye image in each emulsion layer are directly proportional to the intensity of light the film was exposed to. The developing process is generally stopped by removing the film from the developer tank and rinsing the developing solution from the film with water or and acidic solution.
Conventional wet chemical developing processes remove both the silver image and the undeveloped silver halide grains from the film to produce a film negative having only a dye image within the film negative. To remove the silver image and undeveloped silver halide, the developed film is immersed and agitated in a tank of bleaching solution. The bleaching solution chemically oxidizes the metallic silver forming the silver image and converts the silver image into silver halide. The bleached film is then immersed and agitated in a tank of fixer solution. The fixer solution removes the silver halide from the film by substantially dissolving the silver halide crystals. The fixer solution is thereby contaminated with dissolved silver compounds and becomes a hazardous waste byproduct of the wet chemical developing process. The film is then washed, stabilized and dried to produce a conventional film negative. The film negative can then be used to produce a corresponding image on photographic paper by methods known to those skilled in the art.
Conventional film digitization processes scan the film negative using a conventional electronic scanner to produce a digital image that electronically represents the photographed image. Conventional electronic film scanners generally operate by directing white light through the film negative. The light interacts with the dye clouds forming the image and the intensity of the colors red, green and blue are recorded by a sensor. The sensor data is used to produce the digital image.
A relatively new process under development is digital film processing (DFP). DFP systems directly scan the film during the development process. In particular, instead of scanning the dye image in the film, conventional DFP systems scan the silver image formed in the emulsion layers while the film is developing. In conventional DFP systems, the film is scanned using infrared light. Scanning with infrared light prevents the film from being fogged and allows the developing film to be scanned at different times during the development process in order to acquire image data at different exposure levels.
The DFP scanning process is generally accomplished by measuring infrared light reflected from the developed silver image in the front and back emulsion layers, and measuring the infrared light transmitted through the film. The reflected and transmitted light measurements of the film provide data on the blue, red, and green sensitized emulsion layers, respectively. The measured reflected and transmitted light data is processed to produce the digital image.
One embodiment of the invention is an improved digital film processing system. In this embodiment, the improved digital film processing system includes a scanning system and a data processing system. The scanning system scans film and produces sensor data that is communicated to the data processing system. The film scanned by the scanning system includes silver and at least one dye cloud disposed within the film. The silver contained within the film may comprise developed metallic silver, silver halide, or both. The data processing system processes the sensor data to produce a full color digital image. The digital image can be output to any suitable output device, such as a monitor, printer, memory device, and/or the Internet. In a particular embodiment, the digital color film processing system is embodied as a self-service kiosk for processing film.
Another embodiment of the invention is a system for developing and processing film to produce a digital image. In this embodiment, the system includes a film processing system, a scanning system, and a data processing system. The film processing system operates to coat a processing solution onto the film that initiates development of a silver image and at least one dye cloud within the film. In a particular embodiment, the film processing system includes a halt station that operates to retard development of the coated film after the film has been developed for a predetermined amount of time. The halt station may operate by applying a halt solution to the coated film, chilling the film, drying the film, or any other suitable method for slowing the development of the film prior to scanning the film. The scanning system scans at least one of the dye images (cyan, magenta, yellow) within the coated film and outputs sensor data to the data processing system. The scanning system scans the coated film using at least one frequency of light within the visible portion of the electromagnetic spectrum. The data processing system receives and processes the sensor data to produce the digital image. The light used to scan the film may comprise blue light, red light, green light, any combination thereof, and any other suitable light, including infrared light. The scanning system may also operate to scan the film by measuring light transmitted through the film, reflected from the film, reflected and transmitted through the film, or any other suitable combination.
Another embodiment of the invention is a system for digitizing a developed film coated with a processing solution. In this embodiment, the system comprises at least one lighting system and at least one sensor system. The lighting system operates to illuminate the coated film with visible light. The sensor system operates to measure the light from the coated film and produce sensor data. In particular embodiments, the visible light includes blue light, green light, red light, or a suitable combination thereof. In yet another particular embodiment, the lighting system also operates to illuminate the film with infrared light.
Yet another embodiment of the invention is a film processing system. In this embodiment, the film processing system comprises an applicator station and a development station. The applicator station operates to coat a processing solution onto the film, wherein the processing solution initiates development of a silver image and at least one dye image within the film. The development station operates to substantially control the environment surrounding the coated film during development of the film. The film processing system may also include a halt station that operates to retard the development of the film after development of the film. In a particular embodiment, the halt station applies a halt solution to the film. The halt solution may comprise a fixer solution, bleach solution, stop solution, blix (bleach plus fixer) solution, any combination thereof, or any other suitable solution.
One implementation of the invention is a method for developing and digitizing exposed film having multiple emulsion layers containing silver halide. In this implementation, the method comprises coating a processing solution on the film to develop the exposed silver halide grains and produce at least one dye image within the coated film. The coated film is then scanned with light within the visible portion of the electromagnetic spectrum to produce a dye-silver record that is output as sensor data. The sensor data is then processed to produce a digital image. In a particular implementation, processing the sensor data includes processing the dye-silver record using a silver record to substantially remove the effects of silver within the film.
Another embodiment of the invention is the production of digital images produced by digitally processing film that has a silver image and at least one dye image within the film. Digitally processing the film comprises scanning the film with light having at least one frequency within the visible light portion of the electromagnetic spectrum and processing the scan data to produce the digital images. In a particular embodiment, the light used to scan the film comprises red, green, and infrared light. In other embodiments, the film is scanned using light transmitted through the film, reflected from the film, reflected and transmitted through the film, or any other suitable combination.
The invention has several important technical advantages. Various embodiments of the invention may have none, some, or all of these advantages. An advantage of at least one embodiment is that environmentally hazardous effluents are not created by the removal of silver from the film. In particular, no water plumbing is required to process the film in accordance with at least one embodiment of the invention. As a result, this embodiment is less expensive that conventional wet chemical processing systems and can be located at any location. In contrast, conventional wet chemical processing of film requires water plumbing and removes the silver from the film, which produces environmentally hazardous effluents that are controlled by many government regulatory agencies.
Another advantage of at least one embodiment of the invention is that the invention can be embodied in a simple user operated film processing system, such as a self-service kiosk. In this embodiment, skilled technicians are not required, thereby reducing the cost associated with developing and processing film. In addition, at least one embodiment of the invention allows the film to be developed and processed faster than conventional wet chemical processing of the film.
Another advantage of at least one embodiment of the invention is that data corresponding to the dye clouds in the film is used to produce the digital image. In other embodiments, data corresponding to the silver image in the film is also used to produce the digital image. In contrast, conventional digital film processing generally uses infrared light to collect data corresponding only to the silver to produce a digital image. Accordingly, at least one embodiment produces a better digital image than produced by conventional digital film processing.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.